Study of the properties of cermet ferromagnetic materials by the eddy current method

Summary The possibility is shown of applying the eddy current method to the study of the surface layers of electrically conducting ferromagnetic material.A theoretical expression has been derived for the dependence of the resonance voltage on the specific electrical conductivity and magnetic permeability of a material.Experimental data are presented in confirmation of the theoretically derived dependence.     

Microstructural features of the α→β transformation in silicon nitride at high pressures and temperatures

Translated from Poroshkovaya Metallurgiya, No. 12 (360), pp. 50–56, December, 1992.     

Structural transformations in polycrystalline β-Si3N4 at high temperatures and pressures

Translated from Poroshkovaya Metallurgiya, No. 8(356), pp. 5–10, August, 1992.     

Sintering kinetics of ZrO2 nanopowders modified by group IV elements

The sintering behavior of tetragonal zirconia nanopowders modified by the group IV elements at the initial sintering stage was investigated. It was found that different additives SiO₂, SnO₂, and GeO₂ have a significant influence on the densification kinetics of 3Y-TZP nanopowders obtained by coprecipitation during sintering as it depends on the amount of additives (0-5 wt%). The shrinkage of zirconia-based specimens during the nonisothermal sintering was analyzed using the dilatometric data. The constant rate of heating technique was applied in order to determine the dominant mass transfer mechanism at the initial stage of sintering in modified zirconia nanopowders. It was found that there was a change in the mass transfer mechanism and diffusion activation energy in 3Y-TZP as a result of the additives. The dominant sintering mechanism in 3Y-TZP changed from the volume diffusion to the grain boundary diffusion due to the addition of SiO₂ and SnO₂ and the sintering activation energy increased in these cases. However, GeO₂ additive activated the viscous flow mechanism in sintering process of 3Y-TZP nanopowders which led to acceleration of the densification due to the decrease in the diffusion activation energy.     

Thermodynamic simulation of the Ni—Ru binary-system phase diagram

Calculations have given a consistent set of interaction constants for all the phases of variable composition in the Ni−Ru binary system, and also a set of stability constants for the ruthenium phases in its stable and virtual modifications. These data have been used to calculated a phase diagram for the Ni−Ru system. It is found that there is satisfactory agreement between the calculated phase diagram and the experimental one when one uses the subregular solution approximation for the solid and liquid phases of variable composition. Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 5–6(407), pp. 48–55, May–June, 1999.     

The Role of the PFNA Operon of Bifidobacteria in the Recognition of Host’s Immune Signals: Prospects for the Use of the FN3 Protein in the Treatment of COVID-19

Bifidobacteria are some of the major agents that shaped the immune system of many members of the animal kingdom during their evolution. Over recent years, the question of concrete mechanisms underlying the immunomodulatory properties of bifidobacteria has been addressed in both animal and human studies. A possible candidate for this role has been discovered recently. The PFNA cluster, consisting of five core genes, pkb2, fn3, aaa-atp, duf58, tgm, has been found in all gut-dwelling autochthonous bifidobacterial species of humans. The sensory region of the species-specific serine-threonine protein kinase (PKB2), the transmembrane region of the microbial transglutaminase (TGM), and the type-III fibronectin domain-containing protein (FN3) encoded by the I gene imply that the PFNA cluster might be implicated in the interaction between bacteria and the host immune system. Moreover, the FN3 protein encoded by one of the genes making up the PFNA cluster, contains domains and motifs of cytokine receptors capable of selectively binding TNF-α. The PFNA cluster could play an important role for sensing signals of the immune system. Among the practical implications of this finding is the creation of anti-inflammatory drugs aimed at alleviating cytokine storms, one of the dire consequences resulting from SARS-CoV-2 infection.     

Interaction of InAs and InSb with aqueous solutions of nitric acid

InSb dissolution in 7.8–15.6 N HNO₃ is controlled by the oxidizer diffusion to the surface. InAs dissolution in 15.6 N HNO₃ is controlled by diffusion in solution; at low acid concentrations, the dissolution rate is limited by diffusion through the loose oxide layer forming on the sample surface. The different dissolution kinetics of InAs and InSb in HNO₃ can be explained by the different properties of the surface layers of hydrous arsenic and antimony oxides.